Blast furnace tuyere



June 23, 1959 J. E. EBERHARDT 2,891,783

- BLAST FURNACE TUYERE Filed April 11, 1957' 2 Sheets-Sheet 1 1N VENTOR John E. Eberhard! ATTORNEY made of copper or alloys of copper.

United States Patent BLAST FURNACE TUYERE John E. Eberhardt, Bethlehem, Pa., assignor to Bethlehem Steel' Company, a corporation of Pennsylvania Application April 11, 1957, Serial No. 652,176

7 Claims. (Cl. 266-41) This invention relates to improvements in tuyeres and specifically to improvements in tuyeres designed to deliver blast to a blast furnace.

The blast furnace tuyeres in use today are commonly The portion of a tuyere which is subjected to the greatest heat and erosion is the nose portion, which extends beyond the inner face of the furnace wall into contact with the descending furnace charge.

In certain blast furnace tuyeres heretofore used, provision has been made-for supplying cooling water first to the nose portion of the tuyere, the water then flowing through the rest of the body of the tuyere. While delivering the cool water directly to the hottest area is desirable, the full possibilities of such an arrangement have not heretofore been realized, since the rate of flow of the water circulating in the nose portion has been limited-to the rate of flow of the water supplied to the tuyere. I have discovered a way to enhance the cooling effect of the'water in the nose portion of the tuyere.

Cooling at the nose, which is the vulnerable part of a tuyere, is very muchbetter with my invention than with previous types of tuyeres, because of the forced high velocity circumferential circulation and recirculation at the nose. The provision of nose grooves not only assists circulation by giving clean machined surfaces, with im proved heat transfer and reduced frictional drag as compared to a rough as-cast surface, but also increases the area by three to five fold as ribs or fins for water-side heat transfer. Over an extended test period in actual blast furnace operations, 22 tuyeres of my new type exhibited an average service' life of over 200 days, with a maximum life of 424. days, as compared with an average life of 32 days with previous standard types of watercooled tuyeres.

By virtually eliminating the factor of burning, the only service-life-limiting factor remaining to be considered is that of Wear, which is fairly slow andreasonably constant and predictable for each furnace. Delays resulting from tuyere failures can therefore be materially reduced by usingfrnyatuy'eres and replacing them during regularly scheduled shutdowns before they wear out.

It is the principal object of this invention to provide a water-cooled blast furnace tuyere'which will have improved circulation of water in the nose portion.

It is a further object of this invention to provide a blast furnace tuyere which, by reason of improved circulation of water in the nose'portion, will have a service life considerably longer than-'thetuyeres heretofore used.

The foregoing and other objects of my invention will be more fully understood from the following description and claims, together with the drawings, in which Figure l is a longitudinal section of a fabricated tuyere having a constricted nozzle for the cooling Water;

Fig. 2 is a transverse section of the nose of said tuyere, taken on the line 22 of Fig. 1;

Fig. 3 is a longitudinal partial section of the tuyere,

taken on the line 3--3 of Fig. 1, with a wall portion broken away to show the nozzle;

Fig. 4 is a transverse section of an alternative form of nose portion having annular grooves;

Fig. 5 is a longitudinal section of a cast tuyere;

Fig. 6 is a transverse section. through the nose portion on the line 66 of Fig. 5; and

Fig. 7 is a longitudinal section on the line 7-7 of Fig. 5.

Referring to Figs. 1, 2 and 3, the tuyere 10 comprises a main body portion 11 and a nose portion 12 brazed together at 13. The body portion 11 is a frusto-conical hollow casting, of suitable heat conducting metal such as copper or a copper alloy, having the proper dimensions and degrees of outer taper to fit inside a conventional tuyere cooler (not shown). In said body portion 11, the outer wall 14, inner wall 15, and baffle wall 16 form an annular chamber 17 for the circulation of cooling water.

The nose portion 12 is a ring-shaped hollow forging or casting, of copper or copper alloy, which is brazed to the baflie wall 16 of the body portion and forms a second annular chamber 18. For the maximum cooling effect, a plurality of concentric annular grooves 19 may be machined inside the end wall 20 enclosing said annular chamber 18 as shown in Fig. 4, to provide annular ribs or fins 21. It is possible for these grooves 19 to be omitted, particularly where temperatures and other operating conditions of only limited severity need be provided for, in the manner shown in Figs. 1 and 3.

Cooling water is supplied in a direction substantially tangential to the inner wall 22 of said annular chamber 18 of nose portion 12 through the constricted orifice 23 of an angle nozzle 24. Said nozzle 24 may conveniently be formed from a elbow of copper or the like having its discharge end flattened to form a narrow rectangular outlet and with a forwardly extending flat bottom lip 25 having a central hole 26 for a small drive screw 27 fastened in hole 28' in the upper surface of the bafile wall 16. The lower end of said nozzle 23 extends through hole 29 in said balfie wall 16, and is brazed onto a copper tube 30 having a collar 31 expanded to a tight fit in the boss 32 above the threaded inlet hole 33' in end closure 34. ()ther threaded holes 35 in bosses 36 are provided for anchoring means (not shown).

The nose chamber 18 is a continuous circumferential passage, being unobstructed except for the low flat nozzle 24. The provision of a continuous passage. and a flat tangential inlet nozzle, in combination, results in the recirculation of some of the water supplied in the nose chamber 18, and causes the quantity of water .fiowing past any given point in said chamber 18 in a given time to be considerably higher than the quantity of water supplied. to the tuyere inlet 33 over the same period. The increase in flow velocity produced by the constricted nozzle-- appreciably raises the speed of heat transfer, and thus for a given rate of supply of water the withdrawal of heat from the nose portion 12 is greater than would be possible without the effect of thewater recirculation: in chamber 18 aided by the flattened nozzle 24. After circulating in chamber 18,'a portion of the cooling water passes through the pair of openings-37 in the baffle wall 16' and. flows-through the annular chamber 17 in main body portionfi, leaving thebase of the tuyereat-outlet 33 through the boss 39;

Removal for replacement of a damaged nose portion on this fabricated tuyere requires only re-fiuxing and heating of the brazed joint sufiiciently to permit separation from the intact body portion.

Referring now to Figs. 5 to 7 inclusive, the tuyere 40 is a single casting, preferably of copper or copper alloy.

3 The transverse baffle wall 41 divides the interior of the tuyere into two unequal sections, the annular chamber 42 in the nose portion 43 of the tuyere and annular chamber 44 in the main body portion 45. Water passage 46, an integral part of the casting as shown here, supplies cooling water from the inlet end 47 directly to chamber 42, through opening 48 in wall 41. The end of passage 46 which passes through wall 41 is curved and constricted as shown at 49 so as to deliver water in a stream of high velocity substantially at a right angle to passage 46 and in a direction substantially tangential to the inner wall 50 of chamber 42 in a manner similar to that shown in Figs. 1, 2 and 3. Annular nose chamber 42 is continuous, like chamber 18 in Figs. 1-3, permitting free circumferential circulation and recirculation of the water in chamber 42, with the beneficial results above mentioned. The water is discharged from chamber 42 through opening 51 into annular chamber 44 through which it fiows before leaving the tuyere through M outlet 52.

In both forms of tuyere as described above, I have shown the cooling water being delivered first to the nose portion through a passage leading thereto, and this is the design that I prefer. However, most of the benefit of my improved design could still be realized if the water were not delivered to the nose portion first, but were allowed first to flow through the body portion, provided that at the point of entry into the nose portion, the water is given a tangential direction of flow, as described above. In this form, the cooling water would still be caused to circulate and recirculate in a continuous unbroken stream through the annular channel in the nose portion of the tuyere, which is the most important feature of my design. The outlet from the nose portion would be through a pipe or other passage leading directly to the outer end of the tuyere.

Maximum conduction of heat, and thus the most effective cooling, may be had by making the nose portion of the purest copper commercially obtainable, being oxygen free high conductivity copper of 99.95 percent (min) purity.

Where nose failures due to wear have been troublesome, however, some sacrifice of thermal conductivity may be permissible in order to provide a nose portion more resistant to abrasion. Under such conditions, I have found that a nose portion of considerably greater hardness and wear resistance may be cast, or preferably forged, from an alloy having the following nominal chemical composition: copper, 98 percent; nickel, 1.5 percent; and beryllium, 0.5 percent. Another suitable alloy, of somewhat less hardness but slightly better conductivity than the foregoing, has its nominal composition as follows: copper, 99.5 percent, and chromium, 0.5 percent.

Tuyeres constructed according to the foregoing description have proved very successful in actual use. As pointed out above, the greater rate of flow of water in the nose portion of the tuyere permitted by my design accomplishes the removal of a greater quantity of heat from the nose of the tuyere for a given rate of supply of water to the tuyere. The result of this increased cooling eifect is a considerable prolongation of the life of the tuyere.

In the following claims, the expression in one direction is used to indicate that all of the water in the annular channel in the nose portion flows continuously in either a clockwise or a counter-clockwise direction.

The present application is a continuation-in-part of my co-pending application, Serial No. 520,519, filed July 7, I955, for Blast Furnace Tuyere, now abandoned.

Although I have described my invention hereinabove in considerable detail, I do not wish to be limited narrowly to the exact and specific particulars disclosed, but I may also use such substitutes, modifications or equivalents as are included within the scope and spirit of the invention or pointed out in the appended claims.

I claim:

1. A furnace tuyere comprising a body portion, a nose portion connected to said body portion and having a continuous annular chamber therein, a wall between said body and nose portions, means including a constricted nozzle attached to said wall for delivering water to said nose portion in an unbroken high velocity annular stream in one direction, and means in said wall for discharging water from said portion.

2. A furnace tuyere as claimed in claim 1, wherein the nozzle is so formed and disposed as to permit substantially unimpeded annular recirculation of water in said chamber.

3. A furnace tuyere comprising a body portion, a nose portion connected to said body portion and having a continuous annular chamber therein, a wall between said body and nose portions, a conduit extending through said wall for delivering coolant to said annular chamber, said conduit being reduced in area at the point of delivery of coolant to said annular chamber, and an opening in said wall for discharging coolant from said chamber.

4. A furnace tuyere comprising a body portion, a nose portion connected to said body portion and having a continuous annular chamber therein, a wall between said body and nose portions, a conduit extending through said wall for delivering coolant to said annular chamber, said conduit having a constricted orifice arranged at the point of delivery to said annular chamber to project a stream of coolant which stream has a dimension greater in the direction of the plane of said wall than its dimension in a direction normal to said plane, and an opening in said wall for discharging coolant from said chamber.

5. A tuyere comprising a copper body portion including a baffie wall, a nose portion brazed to said body portion and forming a continuous annular chamber with said bafiie wall, the material of said nose portion being a hard copper alloy characterized by high resistance to abrasion and good thermal conductivity, and conduit means extending through the bafiie wall and terminating in a constricted nozzle for delivering coolant to the annular chamber.

6. In a tuyere as claimed in claim 5, the material of said nose portion being an alloy having substantially the following composition: copper, 99.5 percent; and chromium, 0.5 percent.

7. In a tuyere as claimed in claim 5, the alloy of which said nose portion is formed having substantially the following composition: copper, 98.0 percent; nickel, 1.5 percent; and beryllium, 0.5 percent.

References (Iited in the file of this patent UNITED STATES PATENTS 165,561 Goodsell July 13, 1875 2,281,691 Hansel et a1. May 5, 1942 2,735,409 Aurin et a1. Feb. 21, 1956 FOREIGN PATENTS 152,566 Great Britain Oct. 21, 1920 881,260 France Apr. 20, 1943 

